Disentangling the phenotypic variation and pollination biology of the Cyclocephala Sexpunctata species complex (Coleoptera: Scarabaeidae: Dynastinae)

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Abstract

Researching cryptic biodiversity is an integrative process that uses a “total evidence” approach to identify population-level evolutionary lineages (species). Cryptic species of aroids have been discovered but the existence of cryptic pollinator species has not been addressed. The highly polymorphic scarab beetle, Cyclocephala sexpunctata, is a hypothesized pollinator of two cryptic aroid species. This research integrates detailed morphological data, spatial and distribution data, mitochondrial CO1 sequence data and host plant associations to test the hypothesis that cryptic species of Cyclocephala are visiting aroid flowers. Nine morphologically similar Cyclocephala species were included to address identification problems among similar species. A new country record was found for C. pan (Honduras). A female paratype specimen of C. letiranti was determined to be a female C. sexpunctata raising the possibility that there are no female type specimens of C. letiranti. Four unique male paramere forms (morphotypes) were found in C. sexpunctata and the allied species C. brevis. These paramere forms were associated with four female morphotypes that have a diagnostic form of the ventral surface of the epipleural pillow. The ventral form of the female epipleural pillow is described here for the first time and is a new character for the genus Cyclocephala. Detailed elevational and distribution data indicate that the morphotypes of C. sexpunctata and C. brevis are rarely collected together at specific localities. A checklist of cyclocephaline floral associations was compiled. Examination of voucher specimens and published floral associations indicate that the morphotypes described here visit different species of flowers within their hypothesized elevational range. Mitochondrial CO1 data demonstrate that C. sexpunctata is polyphyletic but the monophyly of C. brevis could not be addressed. The combination of these datasets indicates that the morphotypes described here are cryptic species though their taxonomy remains unresolved due to large numbers of synonyms.

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Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Biological Sciences.